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Title: The spectral evolution of the first galaxies. III. Simulated James Webb Space Telescope spectra of reionization-epoch galaxies with Lyman-continuum leakage

In this study, using four different suites of cosmological simulations, we generate synthetic spectra for galaxies with different Lyman-continuum escape fractions (f (esc)) at redshifts $$z\approx 7$$–9, in the rest-frame wavelength range relevant for the James Webb Space Telescope ( JWST) NIRSpec instrument. By investigating the effects of realistic star formation histories and metallicity distributions on the EW(Hβ)–β diagram (previously proposed as a tool for identifying galaxies with very high f (esc)), we find that neither of these effects are likely to jeopardize the identification of galaxies with extreme Lyman-continuum leakage. Based on our models, we expect that essentially all $$z\approx 7\mbox{–}9$$ galaxies that exhibit rest-frame $$\mathrm{EW}({\rm{H}}\beta )\lesssim 30$$ Å to have $${f}_{\mathrm{esc}}\gt 0.5$$. Incorrect assumptions concerning the ionizing fluxes of stellar populations or the dust properties of $$z\gt 6$$ galaxies can in principle bias the selection, but substantial model deficiencies of this type should at the same time be evident from offsets in the observed distribution of $$z\gt 6$$ galaxies in the EW(Hβ)–β diagram compared to the simulated distribution. Such offsets would thereby allow JWST/NIRSpec measurements of these observables to serve as input for further model refinement.
ORCiD logo [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ; ORCiD logo [6] ;  [1] ;  [7] ;  [8] ;  [9]
  1. Uppsala Univ., Uppsala (Sweden)
  2. New Mexico State Univ., Las Cruces, NM (United States)
  3. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); The Univ. of Chicago, Chicago, IL (United States)
  4. Univ. Heidelberg, Heidelberg (Germany)
  5. Osaka Univ., Osaka (Japan)
  6. Osaka Sangyo Univ., Osaka (Japan)
  7. Univ. of Michigan, Ann Arbor, MI (United States)
  8. Univ. of Edinburgh, Edinburgh (United Kingdom)
  9. Instituto de Astrofisica de Canarias, Tenerife (Spain); Univ. de La Laguna, Tenerife (Spain)
Publication Date:
Report Number(s):
FERMILAB-PUB-16-644-AE; arXiv:1608.08217
Journal ID: ISSN 1538-4357; 1484487; TRN: US1700870
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 836; Journal Issue: 1; Journal ID: ISSN 1538-4357
Institute of Physics (IOP)
Research Org:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; dark ages; reionization; first stars; galaxies: high-redshift; techniques: spectroscopic
OSTI Identifier: